1. Field of the Invention
This invention is in the field of electrical recording media for various data, message and graphic imaging devices. More particularly, this application relates to improvements in the preparation of electrosensitive recording media or sheets and the recording density of products produced thereby and commonly referred to as "spark-recording", "burn-off" or "electrosensitive recording" papers, films and foils, having a plurality of layers that are arranged in such a manner that recording is achieved by the local destruction of the required recording layer or layers by means of an electrical signal passing through a stylus spark discharge or other electronic recording member in contact with the surface of the recording media or sheet.
2. Description of the Prior Art
The recording of electrical signals as an image has significantly increased in recent years due to the wide acceptance of facsimile and other telecommunication devices. Recording is generally accomplished on a recording medium or sheet that is regarded as being "surface conductive" or "front grounding" because the current being passed therethrough enters and exits through one of the upper layers of the recording media due to the presence of a plain paper, film or other insulating substrate. Where a conductive paper, foil or other low resistance substrate is used, the recording media or sheet is regarded as being "through conductive" or "back grounding" because the current path travels entirely through the recording media.
The preparation of "front grounding" and "back grounding" recording media or sheets are well-known in the art as exemplified by Miro in U.S. Pat. No. 3,511,700 and Diamond in U.S. Pat. No. 3,920,873.
In using electrosensitive recording sheets, it is most desireable to utilize a sheet that exhibits satisfactory recording densities, that is, a sheet wherein the printed image is of a desired darkness.
It is therefore a significant object of the present invention to improve the image or recording density of images recorded on "surface-conductive" and "through-conductive" recording members or sheets. By image or recording density, it is intended that the darkness or blackness of the recorded indicia be improved.